Mailivery - Reach the Inbox, not the spam folder.
.meteoremails - Send cold emails for free! Free and open source project
Sidemail - The simplest way to send transactional emails. Sidemail makes sending transactional emails trivial, it's perfect for side projects, MVPs or the next big thing.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Postal - Open source mail delivery platform, alternative to Mailgun or Sendgrid
EmailOctopus - Email marketing for less, via Amazon SES